1. Field of the Invention
The present invention is directed to the design and manufacture of integrated circuits. More specifically, but without limitation thereto, the present invention is directed to the design of a wire bond integrated circuit package for high speed I/O.
2. Description of Related Art
An integrated circuit package substrate commonly includes a package substrate having several electrically conductive planar layers separated from one another by electrically insulating layers. Connections between the electrically conductive layers, typically metal layers, are made by forming vias in the electrically insulating layers, typically dielectric layers, and depositing an electrically conductive material in the vias, such as copper. Circuits are formed in the metal layers by etching away a portion of the metal, for example, to form traces in routing metal layers and contact pads in contact pad metal layers. The contact pads are used to make electrical connection between the integrated circuit package and a printed circuit board. Some metal layers in the integrated circuit package are used to conduct a voltage supply and others to conduct a ground return to the routing metal layers and to the contact pad metal layers. In a wire bond package substrate, contact is made between the package and an integrated circuit die by metal bond wires.